You have to create space around your inlet to prevent stuff from getting sucked up. Many HOB's just create a waterfall that dumps into your tank, not much to do about that, just keep it clear under the outflow. Some, like Tetratech models have a tube/funnel that is the outflow, you can attach a tube, like the kind used in a UGF, to it to get the outflow underwater. You can then point the outlet back at the back glass to further blunt the flow.
In general, IMO, lots of circulation is very desireable in a planted tank. It keeps fresh ferts at the leaves, and makes sure your CO2 is everywhere.